Hello
Ive noticed some oddities with the QCImageInputProtocol methods that
work with textures, specifically with regards to texture coordinates
when using more than one input image source.
I have a plugin I am developing which has two image inputs, one for
video input, and one for smaller 256x1 LUT textures, and am attempting
to bind them like so within my
- (BOOL) execute:(id<QCPlugInContext>)context atTime:
(NSTimeInterval)time withArguments:(NSDictionary*)arguments
method:
<snip..>
if(image && [image lockTextureRepresentationWithColorSpace:[image
imageColorSpace] forBounds:[image imageBounds]] &&
lut && [lut lockTextureRepresentationWithColorSpace:[lut
imageColorSpace] forBounds:[lut imageBounds]])
{
[image bindTextureRepresentationToCGLContext:[context CGLContextObj]
textureUnit:GL_TEXTURE0 normalizeCoordinates:NO];
[lut bindTextureRepresentationToCGLContext:[context CGLContextObj]
textureUnit:GL_TEXTURE1 normalizeCoordinates:NO];
// Make sure to flush as we use FBOs and the passed OpenGL context
may not have a surface attached
finalOutput = renderToFBO(cgl_ctx, width, height, bounds, [image
textureName],[lut textureName], lutWidth, lutHeight,
glslProgramObject, amt);
<snip..>
Now, I am passing normalizeCoordinates:NO to
bindTextureRepresentation. my LUT image is 256 x 1 pixels, and 'image'
is some video - esque dimension, like 640x480.
the render to FBO function simply produces an output texture, by
rendering to a texture attachment (this code works in my other
plugins, and was verified to work on the GL list).
Now, I am seeing some oddities with attempting to work with any
texture matrix or coordinate data from texture unit 1, my LUT texture
specifically. I dont get any working values from it.
If I use my texture coordinates like so:
lutTextureCoords = vec2(gl_TextureMatrix[1] * gl_MultiTexCoord1); (in
GLSL)
(which should have the proper coords, since im binding to GL_TEXTURE1
unit, and not normalizing), I get no coords at all (verified by using
a simple texture coord visualizer GLSL shader).
however, If I instead use texure unit 0s coords, I do get a result,
lutTextureCoords = vec2(gl_TextureMatrix[0] * gl_MultiTexCoord0); (in
GLSL)
Also, Ive noticed that *BOTH* GL_TEXTURE0 or GL_TEXTURE1s coordinates
are actually normalized, even though ive asked them not to be, and I
am not touching the GL_TEXTURE_MATRIX manually at all, or loading
identity in glMatrixMode(GL_TEXTURE).
As another data point, ive also noticed similar oddities with texture
unit 1 in the regular GLSL patch (noted a while ago on the mailing
list).
In short, whats the deal with > 1 texture in a custom patch? What
should I be expecting coordinate wise?
Im able to work around the issue, by manually altering the texture
coords myself, but im curious if someone else has noticed these
oddities, or if I am doing anything to cause them.
Thanks,
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Quartzcomposer-dev mailing list ([email protected])
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/quartzcomposer-dev/archive%40mail-archive.com
This email sent to [EMAIL PROTECTED]
